Vulnerability in io.netty:netty-codec-http2 (CVE-2026-56819)
Summary
Vulnerability in io.netty:netty-codec-http2 (CVE-2026-56819). Risk of unauthorized operations or information disclosure. Exploitable via ByteBuf. Mitigation: upgrade to 4.1.136.Final or later.
Original description
The description as published by the source.
Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, a remote unauthenticated peer can leak one direct ByteBuf per HTTP/2 DATA frame in applications that enable HTTP/2 content decompression via DelegatingDecompressorFrameListener. When a DATA frame is processed for a stream whose decompressor has already been closed, Http2Decompressor.decompress(...) calls decompressor.writeInbound(data.retain()) and does not release the retained buffer on the error path, eventually exhausting direct memory and crashing the JVM. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-56819 has been found in io.netty:netty-codec-http2.
Attackers can target a specific entry point like ByteBuf over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade io.netty:netty-codec-http2 to 4.1.136.Final or later.
If unsure, ask your IT team or search "io.netty:netty-codec-http2 CVE-2026-56819" on the vendor's site.
CVE-2026-56819 (io.netty:netty-codec-http2) — CWE-400 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: ByteBuf / DATA / DelegatingDecompressorFrameListener / OutOfMemoryError
Patched: 4.1.136.Final — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-400) exists in io.netty:netty-codec-http2. Attackers reach the vulnerable code path via ByteBuf without authentication.
Check the vendor advisory for the affected versions of io.netty:netty-codec-http2. Attack surface: ByteBuf / DATA / DelegatingDecompressorFrameListener / OutOfMemoryError.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to 4.1.136.Final.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで io.netty:netty-codec-http2 を使っているサービスとバージョンを洗い出す。
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2Apply patch patch
Upgrade io.netty:netty-codec-http2 to 4.1.136.Finalステージング環境で 4.1.136.Final に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-56819 netty
- Ubuntu UBUNTU-CVE-2026-56819 netty
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- patch github.com
- patch github.com
- web github.com
- web github.com
- web github.com